CN104181791B - Image processing system - Google Patents

Abstract

The invention provides an image forming device. The image forming apparatus includes a conveyance guide member and a detection mechanism. The transport guide member guides the recording medium. The detection mechanism detects the presence or absence of the recording medium. The transmission part of the detection mechanism has a shaft part and a detection part that rotates relative to the shaft part by contacting the recording medium. The first guide rib of the conveyance guide member is formed with a cutout portion through which the shaft portion penetrates. The shaft portion is provided with a second guide rib that blocks the opening of the notch portion when viewed from the axial direction of the shaft portion.

Description

image forming device

technical field

The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and the above-mentioned multifunction machine using electrophotography, and more particularly to an image forming apparatus including a transport guide member for guiding a recording medium and a detection mechanism for detecting the presence or absence of a recording medium.

Background technique

Conventionally, in an image forming apparatus employing an electrophotographic process, a common process is to use a developing device to visualize an electrostatic latent image formed on an image carrier such as a photosensitive drum, and transfer the visible image (toner image) to the image carrier. After being attached to the paper (recording medium), a fixing process is performed.

The paper is conveyed with rollers along the conveyance guide, etc. The conveyance guide member is formed of, for example, a plurality of plate-shaped guide ribs arranged at predetermined intervals apart from each other in the width direction of the sheet (direction perpendicular to the sheet conveyance direction).

In addition, a detection mechanism for detecting the presence or absence of paper is provided on the paper feeding path. The detection mechanism includes, for example: a transmission part extending in the width direction of the paper and rotating by contacting the paper; a sensor part detecting the rotation of the transmission part; and the like. The transmission part includes: a shaft part extending in the width direction of the paper, a detection part integrally rotated with the shaft part by contacting the paper, and a rotation part provided on the shaft part and rotating relative to the shaft part.

The transmission part needs to be arranged at a position where it abuts against the paper and does not hinder the conveyance of the paper. Therefore, a notch through which the shaft of the transmission part penetrates is formed in the guide rib, and most of the transmission part is arranged in the conveyance guide member.

According to the above-mentioned conventional image forming apparatus, the paper is conveyed through the paper conveyance path, and when the front end of the paper abuts against the detection part of the transmission part, the transmission part rotates. At this time, due to the rotation of the rotation part, the sensor part detects the rotation of the transmission part, and the detection mechanism determines that there is paper. Then, when the rear end of the paper passes the detection part of the transmission part, the transmission part rotates in the opposite direction and returns to the original state. At this time, the rotation part also rotates in the reverse direction, so that the sensor part detects the reverse rotation of the transmission part, and the detection mechanism determines that there is no paper.

Patent Document 1 Japanese Patent Laid-Open Publication No. 2011-011828

Patent Document 2 Japanese Patent Laid-Open Publication No. 2007-297141

However, in the conventional image forming apparatus, since the transmission part is arranged in the conveyance guide member, a cutout part is formed in the guide rib. Therefore, when the paper is conveyed along the conveyance guide member, the paper may enter the notch (between the inner surface of the notch and the outer peripheral surface of the shaft portion of the transmission part), thereby causing a paper jam.

Contents of the invention

The present invention solves the above problems, and an object of the present invention is to provide an image forming apparatus capable of suppressing jamming of a recording medium from occurring around a detection mechanism for detecting the presence or absence of the recording medium.

An image forming apparatus according to an aspect of the present invention includes a conveyance path through which a recording medium passes, a conveyance member, a conveyance guide member, and a detection mechanism. The transport member is provided on the transport path and transports the recording medium. The conveyance guide member constitutes a conveyance path and guides the recording medium. The detection mechanism is arranged on the transport path and detects the presence or absence of the recording medium. In addition, the detection mechanism includes: a transmission part that rotates by abutting against the recording medium; and a sensor part that detects the rotation of the transmission part. The transmission part includes: a shaft part extending in the width direction which is a direction perpendicular to the conveyance direction of the recording medium; direction to turn. The transport guide member has a base portion and a plurality of first guide ribs standing upright from the base portion, arranged at predetermined intervals in the width direction of the recording medium, and guiding the recording medium. A notch for the shaft of the transmission part to pass through is formed on the first guide rib, and on the position of the shaft corresponding to at least one first guide rib formed with the notch, there is a When viewed from the axial direction of the shaft portion, the second guide rib is provided so as to block the opening of the corresponding notch portion.

According to an image forming apparatus according to an aspect of the present invention, the first guide rib has a cutout portion through which the shaft portion of the transmission portion penetrates. In this way, the shaft portion of the transmission portion can be disposed within the conveyance guide member. That is, it is possible to easily arrange the transmission part at a position where it abuts against the recording medium and does not interfere with conveyance of the recording medium.

In addition, on the shaft portion of the transmission portion, at a position corresponding to at least one first guide rib formed with a notch portion, there is provided a second guide rib protruding radially outward from the shaft portion, and the axial direction of the shaft portion When viewed, the second guide rib is provided so as to block the opening of the corresponding notch. In this way, when the recording medium is conveyed along the conveyance guide member, since the recording medium can be prevented from entering the notch (between the inner peripheral surface of the notch and the outer peripheral surface of the shaft of the transmission part), jamming of the recording medium can be prevented.

Other objects of the present invention and specific advantages obtained by the present invention will be further explained through the following embodiments.

Description of drawings

FIG. 1 is a cross-sectional view schematically showing the structure of an image forming apparatus according to an embodiment of the present invention.

2 is a cross-sectional view showing the structure around a conveyance guide member of an image forming apparatus according to an embodiment of the present invention.

3 is a perspective view showing the configurations of a conveyance guide member and a detection mechanism of the image forming apparatus according to the embodiment of the present invention.

4 is a perspective view showing the configuration around a conveyance guide member of the image forming apparatus according to one embodiment of the present invention.

5 is a perspective view showing the configurations of a conveyance guide member and a detection mechanism of the image forming apparatus according to the embodiment of the present invention.

6 is an enlarged cross-sectional view showing the configuration of first guide ribs and second guide ribs of the image forming apparatus according to the embodiment of the present invention.

7 is a perspective view showing the configurations of a conveyance guide member and a detection mechanism of an image forming apparatus according to an embodiment of the present invention.

8 is an enlarged cross-sectional view showing the structure of a first guide rib and a second guide rib of an image forming apparatus according to an embodiment of the present invention.

FIG. 9 is a perspective view illustrating the configuration of a detection mechanism according to a modified example of the present invention.

detailed description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

An image forming apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8 .

The image forming apparatus 100 (here, a color printer) of this embodiment is a quadruple tandem color printer, and four photosensitive drums 1a, 1b, 1b, 1c and 1d are arranged in parallel to form an image.

In the apparatus main body of the image forming apparatus 100 , four image forming sections Pa, Pb, Pc, and Pd are arranged in order from the left side in FIG. 1 . These image forming parts Pa to Pd are provided corresponding to images of different four colors (yellow, cyan, magenta, and black), and sequentially form yellow, cyan, magenta, and black through the processes of charging, exposure, development, and transfer, respectively. Image.

Photosensitive drums (image carriers) 1a to 1d carrying visible images (toner images) of respective colors are arranged on these image forming portions Pa to Pd, respectively, and the intermediate transfer belt 8 and the intermediate transfer belt 8 rotating counterclockwise in FIG. The respective image forming sections Pa to Pd are provided adjacent to each other. The toner images formed on the photosensitive drums 1a to 1d are sequentially transferred to the intermediate transfer belt 8 moving while abutting the respective photosensitive drums 1a to 1d, and then temporarily transferred to the secondary transfer roller 9. The paper P is further fixed to the paper P which is an example of a recording medium in the fixing device 13 , and then discharged from the main body of the device. Image forming processing is performed on each of the photosensitive drums 1 a to 1 d while rotating the photosensitive drums 1 a to 1 d clockwise in FIG. 1 .

The paper P on which the toner image has been transferred is accommodated in a paper cassette 16 at the lower part of the apparatus, and is transported to the secondary transfer roller 9 by a paper feed roller 12a and a pair of registration rollers 12b. The intermediate transfer belt 8 is a thin sheet body made of dielectric resin, and mainly a non-joint (seamless) belt is used. The intermediate transfer belt 8 and the secondary transfer roller 9 are rotationally driven by a belt drive motor (not shown) at the same linear speed as the photosensitive drums 1a to 1d. In addition, a blade-shaped belt cleaner 17 is disposed downstream of the secondary transfer roller 9 to remove toner and the like remaining on the surface of the intermediate transfer belt 8 .

Next, the image forming sections Pa to Pd will be described. Around and below the rotatably arranged photosensitive drums 1a to 1d are provided charging devices 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d, and for exposing the respective photosensitive drums 1a to 1d based on image data. The exposure unit 5, the developing units 3a, 3b, 3c, and 3d that develop the electrostatic latent images formed on the photosensitive drums 1a to 1d with toner, collect and remove the remaining toner images transferred on the photosensitive drums 1a to 1d developer (toner) cleaning devices 7a, 7b, 7c and 7d.

When image data is input from a host device such as a computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the charging devices 2a to 2d, and then light is irradiated by the exposure unit 5 based on the image data to form a pattern on each of the photosensitive drums 1a to 1d. An electrostatic latent image corresponding to image data. The developing units 3 a to 3 d include developing rollers disposed facing the photosensitive drums 1 a to 1 d, and are filled with predetermined amounts of two-component developers containing toners of cyan, magenta, yellow, and black, respectively.

In addition, when the ratio of the toner in the two-component developer filled in the respective developing units 3a to 3d is lower than a predetermined value due to formation of a toner image to be described later, the toner containers 4a to 4d Toner is supplied to the respective developing units 3a to 3d. The toner is supplied to the photosensitive drums 1 a to 1 d by the developing units 3 a to 3 d, and is electrostatically adhered to form a toner image corresponding to an electrostatic latent image formed by exposure by the exposure unit 5 .

Then, an electric field is applied with a predetermined transfer voltage between the primary transfer rollers 6a-6d and the photosensitive drums 1a-1d from the primary transfer rollers 6a-6d, and the yellow, cyan, magenta, and black on the photosensitive drums 1a-1d The toner image is transferred onto the intermediate transfer belt 8 for the first time. These four-color images are formed in accordance with a predetermined positional relationship predetermined for forming a predetermined full-color image. Subsequently, in preparation for the formation of a new electrostatic latent image, the toner remaining on the surface of the photosensitive drums 1 a to 1 d is removed by the cleaning devices 7 a to 7 d.

The intermediate transfer belt 8 is stretched across the driven roller 10 and the driving roller 11. With the rotation of the driving roller 11 brought by the belt drive motor, the intermediate transfer belt 8 starts to rotate counterclockwise, and the paper P passes from the registration roller to the 12b is conveyed toward the nip (secondary transfer nip) between the secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 and the intermediate transfer belt 8 at a predetermined timing, and is transferred onto the paper P in the nip. A second transfer of the color image. The paper P on which the toner image has been transferred is conveyed to the fixing device 13 .

The paper P conveyed to the fixing device 13 is heated and pressurized when passing through the fixing nip of the fixing roller pair 14 composed of the heating roller 14a and the pressure roller 14b, and the toner image is fixed on the surface of the paper P to form a predetermined shape. full-color image. The paper P on which a full-color image is formed passes through the conveying roller pair 15 and is distributed in the conveying direction by the branching member 21 arranged on the branching part of the paper conveying path 18, and is sent to the duplex conveying path 22 for double-sided copying. ) is discharged to the paper discharge tray 20 by the discharge roller pair 19 .

The paper feeding channel 18 is specifically divided into two branches on the downstream side of the conveying roller pair 15 , and one channel (the channel branching to the left in FIG. 1 ) communicates with the paper output tray 20 . Also, another passage (the passage that branches off to the right in FIG. 1 ) communicates with the double-sided conveyance passage 22 . When images are formed on both sides of the paper P, a part of the paper P passing through the fixing device 13 temporarily protrudes from the discharge roller pair 19 to the outside of the device.

Subsequently, by counter-rotating the pair of discharge rollers 19 and swinging the branching member 21 substantially horizontally, the paper P is guided along the upper surface of the branching member 21 toward the duplex conveyance path 22, and again toward the side with the image side reversed. The secondary transfer roller 9 conveys. Then, the next image formed on the intermediate transfer belt 8 is transferred by the secondary transfer roller 9 to the surface of the paper P on which no image is formed, and the paper P is conveyed to the fixing device 13 and the toner image is fixed. , to the output tray 20.

As shown in FIG. 2 , a transport guide member 30 made of resin for guiding the paper P is disposed above the fixing device 13 (downstream side in the paper transport direction). The conveyance guide member 30 constitutes a part of the paper conveyance path 18 and a part of the duplex conveyance path 22 . By opening the cover member 23, the double-sided conveyance path 22 is exposed. Further, the paper feeding path 18 is exposed by rotating the feeding guide member 30 upward about the upper shaft.

As shown in FIG. 3 , the conveyance guide member 30 includes a plurality of plates arranged at predetermined intervals from each other in the width direction of the paper P (the direction perpendicular to the paper conveyance direction, the direction perpendicular to the paper surface of FIG. 2 ) and guiding the paper P. Shaped guide ribs 31; and a guide curved surface 32 (also refer to FIG. The guide rib 31 constitutes a part of the paper conveyance path 18 , and the guide curved surface 32 constitutes a part of the double-sided conveyance path 22 . In other words, the conveyance guide member 30 includes a base portion (guide curved portion 32) and a guide rib 31 erected from the base portion, and one surface of the conveyance guide member 30 on which the guide rib 31 is provided will be positioned at the image forming portion Pa. The paper P after image formation in ~ Pd is guided to the discharge roller pair 19 (discharge section), and the other surface formed on the back surface of the base part reverses the paper P conveyed from the discharge roller pair 19 to the double-sided conveyance path. 22 to boot.

Furthermore, as shown in FIG. 2 , near the upper side (downstream side in the paper conveying direction) of the fixing roller pair 14 in the paper conveying path 18 , a detection mechanism 40 for detecting the presence or absence of paper P is provided. As shown in FIG. 3 , the detection mechanism 40 is provided only on one side (the left side in FIG. 3 ) from the center of the paper passing area. The detection mechanism 40 includes: a transmission part 41 extending in the width direction of the paper P and rotating by abutting against the paper P; A link (not shown) etc. that is driven (swinged, etc.) by the rotation of a later-described rotating portion 45 of the transmission unit 41 is provided, and the sensor unit 42 detects the rotation of the transmission unit 41 by detecting the drive of the link. In addition, the sensor part 42 may be comprised so that it may directly detect the rotation of the rotation part 45 mentioned later of the transmission part 41. As shown in FIG.

The transmission part 41 needs to be disposed at a position where it abuts against the paper P and does not hinder the conveyance of the paper P. Therefore, among the plurality of guide ribs 31 , the first guide rib 33 disposed on the left side (the side away from the center of the paper passing area) is formed with a notch through which a shaft 43 , which will be described later, of the transmission unit 41 penetrates. 33a. The cutout portion 33a is formed at a front portion of the first guide rib 33 (a portion constituting the paper feeding path 18). Moreover, most of the transmission part 41 is arrange|positioned in the conveyance guide member 30. As shown in FIG.

The transmission part 41 includes: a shaft part 43 rotatably supported by the transport guide member 30 and extending in the width direction of the paper P; The detection part 44 which rotates the shaft part 43 to a conveyance direction;

The shaft portion 43 is formed to extend from the central portion of the paper passing area (central portion of the transport guide member 30 ) to one side (the left side in FIG. 3 ) to the outside of the paper passing area. The detection unit 44 is fixed to the other end (the right end in FIG. 3 ) of the shaft 43 , is arranged at the center of the paper passing area, and is formed to protrude into the paper feeding path 18 . The rotating portion 45 is disposed outside the paper passing area, and is fixed to one end (the left end portion in FIG. 3 ) of the shaft portion 43 .

In addition, as shown in FIGS. 5 and 6 , the shaft portion 43 is provided with a second guide rib 46 that blocks (coincides with) the opening of the notch portion 33 a when viewed from the axial direction of the shaft portion 43 . The second guide rib 46 protrudes radially outward from the shaft portion 43 so as to correspond to at least one first guide rib 33 formed with the notch portion 33a, and closes the opening of the corresponding notch portion 33a. The second guide rib 46 is provided on the outer side of the paper passing area in the shaft portion 43 . Specifically, the second guide rib 46 is disposed on the inner side of the end portion of the paper passing area. That is, the second guide rib 46 is arranged at a position where the curled front edge (end in the width direction) of the paper P is likely to be caught. In addition, the second guide rib 46 is fixed on the shaft portion 43 and rotates integrally with the shaft portion 43 .

In FIGS. 5 and 6 , the paper P is conveyed from the lower side to the upper side. In the state before the paper P abuts against the lower surface of the detection portion 44 (the state of FIGS. 5 and 6 ), as viewed from the axial direction of the shaft portion 43 , the second guide rib 46 closes the part of the notch portion 33 a closer to the shaft portion 43 than the shaft portion 43 . The opening 33b of the portion on the lower side (upstream side in the paper conveyance direction). In addition, in the state where the paper P is in contact with the detection portion 44 and the transmission portion 41 is rotated clockwise in FIG. 46 closes the opening 33c of the cutout portion 33a on the downstream side (upper side) of the shaft portion 43 in the paper conveyance direction. In addition, in the state where the paper P is in contact with the detection part 44 and the transmission part 41 is rotated (the state of FIGS. 7 and 8 ), the upper side of the first guide rib 33 (downstream in the paper conveying direction) is viewed from the axial direction of the shaft part 43 . The angle θ formed by the part of the side) and the second guide rib 46 is an obtuse angle. In this way, since the second guide rib 46 is smoothly connected to the first guide rib 33 , it is possible to suppress the paper P from being caught at the intersection of the second guide rib 46 and the first guide rib 33 .

In addition, as shown in FIG. 6, even in the state before the paper P abuts against the detecting portion 44, the second guide rib 46 can block the portion above the shaft portion 43 in the notch portion 33a as viewed from the axial direction of the shaft portion 43. The opening 33c of the part on the side (the downstream side in the paper conveyance direction). At this time, it is preferable that the angle θ formed by the upper portion of the first guide rib 33 and the second guide rib 46 is an obtuse angle when viewed in the axial direction of the shaft portion 43 even before the sheet P abuts against the detection unit 44 . .

As shown in FIG. 5 , the paper contact portion of the second guide rib 46 is arranged on the lower side (upstream side in the paper conveyance direction) than the paper contact portion (lowest part) of the detection unit 44 when viewed in the axial direction of the shaft portion 43 . ). In this way, the second guide rib 46 comes into contact with the paper P earlier than the detection part 44 with respect to the paper P being conveyed.

In the image forming apparatus 100 described above, when the paper P is transported through the paper feeding path 18 , the front end of the paper P comes into contact with the second guide rib 46 before the contact detection portion 44 . At this time, since the second guide rib 46 closes the opening 33b of the cutout 33a below the shaft 43 (upstream in the paper conveying direction), the paper P does not enter the cutout 33a.

Then, when the front end of the paper P comes into contact with the detection unit 44 of the transmission unit 41 , the transmission unit 41 is rotated in the clockwise direction as shown in FIG. 6 . At this time, the second guide rib 46 guides the paper P upward (downstream side in the paper conveying direction) while keeping it away from the notch portion 33 a. Then, due to the rotation of the rotation part 45 , the sensor part 42 detects the rotation of the transmission part 41 , and the detection mechanism 40 determines that the paper P is present. In addition, in the state where the paper P rotates the transmission part 41 (the state in FIGS. 7 and 8 ), viewed from the axial direction of the shaft part 43, since the second guide rib 46 blocks the part of the notch part 33a that is closer to the shaft part 43 The opening 33c of the upper part prevents the paper P from entering the cutout 33a.

Subsequently, after the rear end of the paper P passes through the detection part 44 of the transmission part 41, due to the self-weight of the detection part 44, etc., a downward moment acts on the rotating shaft, so that the transmission part 41 is reversed (circling in the counterclockwise direction in FIG. 8 ) to rotate and return to the original state (the state of Fig. 5 and Fig. 6, standby state). At this time, the rotating part 45 also rotates in the reverse direction (counterclockwise in FIG. 8 ), so that the sensor part 42 detects the reverse rotation of the transmission part 41, and the detection mechanism 40 determines that there is no paper P. Therefore, when the paper P remains in the paper feeding path (conveyance path) 18 located downstream of the fixing roller pair 14, if it is judged by the sensor unit 42 that the paper P has been present for a predetermined time or longer, it is detected that a jam of the paper P has occurred. .

In the present embodiment, as described above, the first guide rib 33 is formed with the cutout portion 33a through which the shaft portion 43 of the transmission portion 41 penetrates. In this way, the shaft portion 43 of the transmission portion 41 can be arranged inside the transport guide member 30 . That is, the transmission unit 41 can be easily arranged at a position where it abuts against the paper P and does not hinder the conveyance of the paper P. As shown in FIG.

In addition, the shaft portion 43 of the transmission portion 41 is provided with a second guide rib 46 that blocks the opening of the notch portion 33 a of the first guide rib 33 when viewed from the axial direction of the shaft portion 43 . In this way, when the paper P is conveyed along the conveyance guide member 30, since the paper P can be prevented from entering the notch 33a (between the inner peripheral surface of the notch 33a and the outer peripheral surface of the shaft part 43 of the transmission part 41), it is possible to suppress the generation of the paper P. P's paper jam.

Specifically, as described above, in the state before the paper P abuts against the detecting portion 44, the second guide rib 46 blocks the lower side of the notch portion 33a than the shaft portion 43 (upstream in the paper conveying direction) when viewed in the axial direction of the shaft portion 43. side) part of the opening 33b. In this way, entry of the paper P into the opening 33b of the portion below the shaft portion 43 in the notch portion 33a can be suppressed.

In addition, in the state where the paper P abuts against the detection portion 44 and rotates the transmission portion 41 , the second guide rib 46 closes the upper side of the notch portion 33 a than the shaft portion 43 as viewed in the axial direction of the shaft portion 43 . Opening 33c. In this way, entry of the paper P into the opening 33c of the portion above the shaft portion 43 in the notch portion 33a can be suppressed.

In addition, as described above, in the state where the paper P abuts against the detection portion 44 and the transmission portion 41 is rotated, the portion of the first guide rib 33 above the shaft portion 43 is aligned with the first guide rib 33 when viewed in the axial direction of the shaft portion 43 . The angle θ formed by the two guiding ribs 46 is an obtuse angle. In this way, it is possible to prevent the front end of the paper P from entering the intersection of the portion above the shaft portion 43 of the first guide rib 33 and the second guide rib 46 to make it difficult to pull out, so that jamming of the paper P can be further suppressed. Paper.

Furthermore, as described above, the second guide rib 46 rotates relative to the shaft portion 43 . In this way, the paper P can be guided upward (downstream in the paper transport direction) by the rotation of the second guide rib 46 , so that jamming of the paper P can be further suppressed.

Furthermore, as described above, the second guide rib 46 abuts against the paper P prior to (or simultaneously with) the detection portion 44 . In this way, it is possible to suppress rotation of the transmission portion 41 before the paper P abuts against the second guide rib 46 . Therefore, it is possible to suppress the opening 33 b of the cutout portion 33 a below the shaft portion 43 from being opened and the paper P entering this portion. In this way, jamming of the paper P can be suppressed.

In addition, as described above, the second guide rib 46 is provided at a position outside the paper passing area in the shaft portion 43 (near the inside of the position where the widthwise end of the large-sized paper passes). Since the edge of the paper P is easily curled when the size of the paper P is increased, the curled leading edge of the paper P can easily enter the cutout 33 a at a position outside the paper passing area. Therefore, it is particularly effective to provide the second guide rib 46 at a position outside the paper passing area in the shaft portion 43 .

Furthermore, as described above, the conveyance guide member 30 and the detection mechanism 40 are arranged on the downstream side in the sheet conveyance direction with respect to the fixing device 13 . Since the paper P passing through the fixing device 13 is easily curled due to heat and pressure during fixing, jamming of the paper P is likely to occur downstream of the fixing device 13 in the paper conveyance direction. Therefore, arranging the conveyance guide member 30 and the detection mechanism 40 on the downstream side of the fixing device 13 in the paper conveying direction is particularly effective in suppressing jamming of the paper P passing through the fixing device 13 .

In addition, all the features of the embodiments disclosed this time are illustrative and not restrictive. The scope of the present invention is not limited to the above-described embodiments but is shown by the claims, and includes substantially the same contents as the claims and all changes within the scope.

For example, application of the present invention to a color printer has been described as an example, but the present invention is not limited thereto. Of course, the present invention can be applied to various image forming apparatuses such as monochrome printers, color copiers, monochrome copiers, digital multifunction machines, facsimile machines, etc., which are provided with transport guide members for guiding recording media and detection mechanisms for detecting the presence or absence of recording media.

In addition, the above-mentioned embodiment shows an example in which the present invention is applied to the conveyance guide member and detection mechanism arranged on the downstream side of the fixing device in the paper conveying direction, but the conveying guide arranged on the part other than the downstream side of the fixing device in the paper conveying direction Components and detection mechanisms can also apply the present invention.

Furthermore, the above-mentioned embodiment has shown an example in which the second guide rib is provided only at a position outside the paper passing area in the shaft portion, but the present invention is not limited thereto. For example, in the modified example of the present invention shown in FIG. 9, the second guide rib 46 can be arranged on both the outer position and the inner position than the paper passing area in the shaft portion 43, that is, it can be much different from the width. corresponding to the ends in the width direction of each sheet. According to the above configuration, not only large-sized paper P but also small-sized paper P can suppress the occurrence of paper jams.

In addition, the above-mentioned embodiment shows an example in which the second guide rib rotates integrally with the shaft, but the present invention is not limited thereto, and the second guide rib may not rotate integrally with the shaft.

Claims (10)

1. An image forming device, characterized in that, comprising: The conveying channel through which the recording medium passes; a conveying member disposed on the conveying path and conveying the recording medium; a conveyance guide member constituting the conveyance path and guiding the recording medium; and a detection mechanism arranged on the transport path and detects the presence or absence of the recording medium, The detection mechanism includes: a transmission part that rotates by abutting against the recording medium; and a sensor part that detects the rotation of the transmission part, The transmission part includes a shaft part extending in a width direction perpendicular to a conveying direction of the recording medium, and a detection part protruding radially outward from the shaft part, By contacting the recording medium and rotating relative to the shaft portion in the conveying direction, The transport guide member has a base portion and a plurality of first guide ribs. The plurality of first guide ribs are erected from the base portion and arranged at predetermined intervals in the width direction of the recording medium. booting the recording medium, A notch through which the shaft of the transmission part passes is formed on at least a part of the first guide ribs of the plurality of first guide ribs, On the shaft portion, a first guide rib protruding radially outward from the shaft portion is provided at a position corresponding to at least one of the first guide ribs formed with the notch portion. Two guiding ribs, Viewed from the axial direction of the shaft portion, the second guide rib is arranged to block the corresponding opening of the notch portion. 2. The image forming apparatus according to claim 1, wherein: In the state before the recording medium abuts against the detection part, the second guide rib blocks the notch part upstream of the recording medium conveyance direction from the shaft part as viewed in the axial direction of the shaft part. The opening of the side part. 3. The image forming apparatus according to claim 1 or 2, wherein: In the state where the recording medium abuts against the detection part and the transmission part is rotated, the second guide rib blocks the notch part more than the shaft when viewed from the axial direction of the shaft part. The opening of the portion on the downstream side of the recording medium conveyance direction. 4. The image forming apparatus according to claim 3, wherein: In the state where the recording medium abuts against the detection part and the transmission part is rotated, the first guide rib is located on the downstream side in the recording medium conveyance direction as viewed from the axial direction of the shaft part. The angle formed by intersecting with the second guide rib is an obtuse angle. 5. The image forming apparatus according to claim 1 or 2, wherein: The recording medium abutting portion of the second guide rib is arranged upstream in the recording medium conveyance direction from the recording medium abutting portion of the detection unit when viewed in the axial direction of the shaft portion. 6. The image forming apparatus according to claim 5, wherein: The second guide rib abuts against the transported recording medium prior to the detection portion. 7. The image forming apparatus according to claim 1 or 2, wherein: The second guide rib is provided on a region of the shaft portion where the end portion in the width direction of the recording medium passes. 8. The image forming apparatus according to claim 7, wherein: A plurality of second guide ribs are provided, The plurality of second guide ribs are respectively arranged corresponding to widthwise ends of different recording media. 9. The image forming apparatus according to claim 1 or 2, wherein: having a fixing device for fixing the toner image on the recording medium, The conveyance guide member and the detection mechanism are disposed on a downstream side in a recording medium conveyance direction with respect to the fixing device. 10. The image forming apparatus according to claim 1 or 2, wherein: The conveyance guide member is arranged on the downstream side of the conveyance direction of the image forming unit, and one surface of the conveyance guide member on which the first guide rib is provided discharges the recording medium on which the image is formed in the image forming unit. part, and the other surface of the conveyance guide member formed on the rear surface of the base part guides the recording medium inverted and conveyed from the discharge part to the double-sided conveyance path.